Composites of iron oxide nanoparticles immobilized on the surface of various clay mineral matrices (muscovite, montmorillonite and vermiculite) have been prepared by the alkaline oxidative hydrolysis of iron sulphate in the presence of mineral matrices. The composites have been studied by Mössbauer spectroscopy, XRD, TEM and SQUID. Correspondence between the hyperfine parameters and the iron oxide particle size and magnetic behaviour has been proved. The prepared composites differ in magnetic properties, size and morphology of the iron oxide particles.